Re: "chmod -w file" now complains if file is still writable afterwards

[Paul Eggert]

address@hidden (Eric Blake) writes:

> Other questions, though - with our extension options, should we interpret
> `chmod -w a+x foo' the same as `chmod -- -w ./a+x ./foo' or like
> `chmod -- -w,a+x ./foo'?

It's been the former for a while; I guess that's OK.

> POSIX allows modes that look like long options - can the code be
> made to treat `chmod --w foo' the same as it would `chmod -w foo' by
> seeing if unrecognized long options match a valid mode string?

Not in general, because plain "--" is a valid mode option, but POSIX
specifies a different meaning for "--".  I don't think it's worth
worrying much about other leading-"--" forms, as nobody is likely to
use them (unlike "-w", say).

> Speaking of which, the `chmod --help' wording could be improved (perhaps
> with examples); it does not mention -w, -r, etc. as being extension options,

I doubt whether this level of detail needs to be in the usage; usage
is just meant to be a brief reminder, not a formal spec.

> and wrongly states that "one or more of the letters ugoa" is required as who,
> and "one or more of the letters rwxXstugo" is required as perm/permcopy.

Good point.  That's fixed in CVS.  It now says:

Each MODE is of the form `[ugoa]*([-+=]([rwxXst]*|[ugo]))+'.